Method and means for mounting annular inside diameter blade concentrically and in circumferential tension



3,324,53@ IAMETER BLADE Jame w, 1967 c. E. CLELAND METHOD AND MEANS FORMOUNTING ANNULAR INSIDE D CONCENTRICALLY AND IN CIRCUMFERENTIAL TENSIONFiled May 5, 1965 5 Sheets-Sheet 1 3,324 METHOD AND MEANS FOR MOUNTINGANNULAR INSIDE DIAMETER BLADE June l3, (3. E. CLELAND CONCENTRICALLY ANDIN GIRCUMFERENTIAL TENSION Filed May 5, 1965 5 Sheets-Sheet 2 'Q'MWJ/m/WZZZ-wi s .EI MZand June 13, 1%? c. E. mash/mt) 3,324,539

METHOD AND MEANS FOR MOUNTING ANNULAR INSIDE DIAMETER BLADECONCENTRICALLY AND IN CIRCUMFERENTIAL TENSION Filed May 5, 1965 5Sheets-Sheet 3 Jaime M, WW7 c. E. CLEILAND 3,324,53

IAMETER BLADE METHOD AND MEANS FOR MOUNTING ANNULAR INSIDE DCONCENTRICALLY AND IN CIRCUMFERENTIAL TENSION Filed May 5, 1965 5Sheets-Sheet 4 5255 .E'. C'Zelarm June 3, WW7 c E. CLELAND METHOD ANDMEANS FOR MOUNTING ANNULAR INSIDE DIAMETER BLADE CONCENTRICALLY AND INCIRCUMFERENTIAL TENSION Filed May 5, 1965 I 5 Sheets-Sheet 5 I I 53 l 7Z K 20 3 I. I A?) 54 I 5 13 3,324,539 METHUD AND MEANS FQR MOUNTKNGANNU- LAR HNSEDE DIAMETER BLADE CONCENTRI- CALLY AND INCIRCUMFEREJENTIAL TENSIUN Charles E. Cleland, Minneapolis, Minn,assignor to Continental Machines, inc, Savage, Minn, a corporation ofMinnesota Filed May 3, 1965, Ser. No. 452,603 8 Claims. (Cl. 229-406)ABSTRACT F THE DISCLOSURE A thin annular inside diameter cutting bladehaving its peripheral edge portion loosely received between a pair ofclamping rings is firmly held in a flat condition while the rings areshifted in unison, edgewise of the blade, as needed to bring the ringsinto concentricity with the blade. The direction or directions the ringsmust be shifted and the extent thereof is determined by reference to anoptically observed spacial relationship between the inner cutting edgeof the blade and a circumferential surface on one of the rings. Whenconcentricity is established the rings are drawn together to clamp theblade therebetween.

This invention pertains to cutting tools of the type comprising a thinannular blade with an inside diameter cutting edge, and the inventionrelates more particularly to a method and means for mounting such ablade in true concentric relation to a chuck by which the blade isrotatably carried and for applying tensioning force to the bladeuniformly all around the same.

Annular blades of the type with which this invention is concerned,sometimes referred to as inside diameter blades, are made of very thinstock and have diamond bort around the inside edge of the blade. Suchblades, because of their thinness, are now generally used for slicingcrystals of germanium, silicon, quartz and the like in the manufactureof electronic components, because the narrow kerf produced by an insidediameter blade conserves valuable crystal material. However, themounting of such a blade presents serious problems arising out of itslack of rigidity. It is of obvious importance that the blade be mountedtruly concentrically in the chuck by which it is carried, in order toavoid radial chatter as the blade is rotated in cutting engagement witha workpiece. It is also important, in order to prevent fiatwisedisplacement of an inside diameter blade during cutting, that it bemounted in tension, and that such tension be uniform all around theblade.

While the tensioning of the blade is achieved by applying radial forceto the blade in a zone spacedly radially from its inner edge, theapplication of such force produces circumferential stresses near theinside diameter cutting edge and is therefore referred to hereinafter ascircumferentially stressing or tensioning the blade.

Such expedients as have heretofore been employed for achievingconcentricity and circumferential stressing of a thin annular blade withan inside diameter cutting edge have not been completely satisfactory.In one prior arrangement the blade was secured to a chuck by means of aclamping ring, and the opposing annular faces of the chuck and clampingrings were respectively provided with a rounded concentric groove andwith a mating rounded projection. The projection on the one forced theflat contacting area of the periphery of the blade into the groove inthe other as the ring was fastened to the chuck, therebycircumferentially stressing the blade. Once a blade had been clampedbetween the chuck and clamping ring of this arrangement, it waspermanently deformed by 3,3245% Patented June 13, l d'l' the cooperatingprojection and groove, and therefore if the blade was not established inconcentricity to the chuck when the clamping ring was tightened, theblade had to be discarded unused. Unfortunately the arrangement justdescribed made no provision for accurately positioning the blade inconcentric relation to its chuck.

In another arrangement, the peripheral portion of the blade was clampedbetween a pair of rings having opposing flat faces, and the ringscooperated to provide a holder that could be concentrically secured to achuck. A tension ring having a concentric axially inwardly projectingannular portion was screwed into one of the rings until it engaged theblade and displaced the central portion thereof a small distance axiallyinwardly. The axial offset of the central portion of the blade that wasmaintained by the tension ring effected the necessary circumferentialtensioning of the blade, but did so at the expense of imposingunpredictable and undesired torsional stresses upon the blade due tofriction between the blade and the tension ring as the latter wasrotated in engagement with the blade, so that there could be noassurance that circumferential tension was uniform all around the blade.

With these and other objections to prior expedients in mind, it is ageneral object of the present invention to provide a method and meansfor establishing a thin annular blade having an inside diameter cuttingedge in true concentric relation to a chuck by which the blade isrotatably carried, and for circumferentially tensioning the bladeuniformly all around the same without imposing unwanted torsional orother stresses upon the blade; and to achieve these ends, moreover, in afacile and expeditious manner, with relatively simple and inexpensiveapparatus, and without entailing any risk of damaging the blade beforeit is used.

Another and more specific object of this invention is to provide asimple fixture which is adapted to cooperate with a pair of clampingrings that provide a holder by which a blade of the character describedcan be mounted on a chuck, which fixture enables a blade to beestablished in true concentricity to the clamping rings, and hence tothe chuck, Without requiring the imposition of any stress or strain uponthe blade and Without any necessity for touching the cutting edge of theblade.

A further specific object of this invention is to provide a quick andeasy method of centering an annular blade with respect to a pair ofclamping rings that provide a holder by which the blade can beconcentrically mounted on a rotatable chuck, in which method the bladeis clampingly confined against edgewise motion while the clamping rings,locked into concentric relationship with one another with their opposingsurfaces lightly fiat-wise engaging the peripheral portions of the bladeat opposite faces thereof, are shifted in unison as required to bringthem into concentricity with the blade; and then, while the rings aremaintained in concentric relation to the blade, they are drawn togetherand releasably locked in clamping relationship to the blade.

Still another specific object of this invention is to provide apparatusfor radially tensioning an annular blade which is clamped between a pairof clamping rings that provide a holder by which the blade can beconcentrically mounted on a chuck, said apparatus comprising a tensionring receivable in one of the clamping rings, and force applying meansfor imparting an axial purely translatory motion to the tension ring toforce it into tensioning engagement with the blade, said force applyingmeans preferably having elements in common with the above mentionedfixture for centering the blade in the clamping rings.

It is also a specific object of this invention to provide a method ofestablishing circumferential tension in an annular blade clamped betweena pair of clamping rings, in which method axial force is applieduniformly and simultaneously at all points around a tension ring that isreceived in one of the clamping rings, to advance the tension ring intothe clamping ring with an axial purely translatory motion until thetension ring reaches a position at which it holds the central portion ofthe blade axially offset by a predetermined amount from the peripheralportion of the blade; and, while the tension ring is held in saidposition by the continued application of coaxial force thereto, it isreleasably locked to one of the clamping rings.

With the above and other objects in view which will appear as thedescription proceeds, this invention resides in the novel "method andapparatus substantially as hereinafter described and more particularlydefined by the appended claims, it being understood that such changes inthe precise embodiment of the hereindisclosed invention may be made ascome within the scope of the claims.

The accompanying drawings illustrate one complete example of thephysical embodiment of the invention constructed and practiced accordingto the best mode so far devised for the practical application of theprinciples thereof, and in which:

FIGURE 1 is a fragmentary view, partly in side elevation and partly invertical section, of a machine tool which incorporates a thin annularblade having an inside diameter cutting edge, the work supporting tableand related portions of the machine tool bing omitted;

FIGURE 2 is a front perspective view of the chuck of the machine toolshown in FIGURE 1 with an annular inside diameter cutting blade mountedin a holder concentrically carried by the chuck;

FIGURE 3 is an exploded perspective view of the components comprisingthe chuck, holder and blade assembly shown in FIGURE 2;

FIGURE 4 is a vertical sectional view of a fixture that can be employedaccording to the principles of this invention for centering an annularblade with respect to the clamping rings that comprise the holder forthe blade, the blade and clamping rings being shown in their operativerelation to the fixture for the practice of the centering procedure;

FIGURE 5 is a top perspective view of the fixture illustrated in FIGURE4, shown in its condition for preliminarily centering the blade andclamping rings relative to one another:

FIGURE 6 is a top perspective view of the fixture illust-rated in FIGURE4, shown in its condition for finally and accurately bringing the bladeand clamping rings into true concentricity;

FIGURE 7 is a top plan view of the fixture, in the condition illustratedin FIGURE 6;

FIGURE 8 i; a top perspective view of the fixture shown in FIGURES 4-7,but in its condition for use in establishing the tension ring in itsposition at which it imposes the desired circumferential tension uponthe blade; and

FIGURE 9 is a vertical sectional view of the fixture in the conditionillustrated in FIGURE 8.

Referring now more particularly to the accompanying drawings, thenumeral 5 designates generally the cutting head portion of a machinetool having a cup-shaped rotatable chuck 6 on which there is coaxiallymounted a thin annular blade 7 having an inside diameter cutting edge.The chuck is carried on a coaxial rearwardly projecting spindle 8mounted in a suitable bearing head 9 and rotatably driven, through abelt transmission 10, by an electric motor 11.

The annular blade 7 is concentrically mounted on the rim of thecup-shaped chuck by means of a blade holder 12 that comprises front andrear clamping rings 13 and 14 that engage around the outer marginal edgeportion of the blade. Therear clamping ring 14 abuts a flat forwardlyfacing surface 16 on the rim of the chuck, and the blade holder 12 isreleasably secured to the chuck by cap screws 18 which extend throughthe two clamping rings and are threaded into the chuck. Locating pins 19on the chuck (see FIGURE 3), projecting forwardly from its rim to bereceived in closely fitting holes in the rear clamping ring, serve toaccurately establish the blade holder in concentric relation to thechuck.

The blade is maintained under circumferential tension by means of atension ring 17 which is secured to and partly received in the frontclamping ring 13, and which holds the central portion of the bladeaxially offset from its outer marginal edge portion.

As is conventional, the inner marginal edge portion of the annular blade7 is coated with diamond bort, as at 20. Means (not shown) may beprovided for delivering liquid cooling medium to the blade, and thecylindrical wall of the cup-shaped chuck may be provided withcircumferentially spaced ports or outlets 21 through which such liquidcan escape into a collector housing 22 that surrounds the chuck andblade assembly.

The cooperating clamping rings 13 and 14 that comprise the blade holder12 have opposing fiat axially inner faces 13' and 14' between which theblade is clampingly confined, and their axially outer faces are likewiseflat and are parallel to their axially inner faces. The two clampingrings preferably have equal inside and outside diameters, but the rearclamping ring 14 has a somewhat greater axial thickness than the frontclamping ring 13. One of the clamping rings (preferably the front ring13) has locating pins 23 projecting therefrom and receivable in closelyfitting holes in the other clamping ring, so that said two rings can belocked in accurately concentric relation to one another while theiraxially inner faces are lightly fiatwise engaged with a blade betweenthem. The clamping rings can be drawn together and secured in clampingrelation to the blade by means of a plurality of cap screws 24 thatextend through circumferentially equi-spaced holes 25 in the rearclamping ring and into coaxial threaded holes 26 in the front clampingring.

It will be apparent that the several locating pins 19 and 23 serve toestablish the clamping rings in accurate coaxial relationship to oneanother and to the chuck 6, and hence if a blade 7 is established inconcentric relationship to the clamping rings 13 and 14 it will beconcentric to the chuck. Centering the blade relative to the rings canbe accomplished easily and accurately by means of the method of thisinvention, which is readily practiced with the aid of a fixture 28illustrated in FIGURES 4-7.

Briefly, the method of this invention consists in clampingly confiningthe blade between a pair of clamping members having opposing fiatclamping surfaces and which leave the central portion of the bladevisible around substantially the entire inner edge thereof; disposingthe clamping rings 13 and 14 in assembled relation to the blade but withtheir axially inner faces 13' and 14' in only light fiatwise contactwith opposite faces of the blade, the locating pins 23 being utilized toestablish and maintain the clamping rings in concentric relationship toone another; then, by reference to the inner edge of the blade and acircumferential surface on one of the clamping rings, shifting theclamping rings in unison and edgewise relative to the blade until theclamping rings are accurately concentric to the blade; and finally,while holding the clamping rings against displacement relative to theblade, tightening the cap screws 24 to draw the clamping rings axiallytoward one another and releasably lock them in clamping relationship tothe blade.

The fixture 28 (see FIGURES 4 and 5) comprises a base 29 that has anannular upwardly facing fiat surface 30 surrounding a raised centralboss 31 with a flat upper surface 32. A central stud or post 33 havingits upper end portion threaded as at 34 projects coaxially upwardly fromthe boss.

The height of the central boss 31 is equal to the axial thickness of thefront clamping ring 13, and the latter is adapted to rest on the annularsurface 30 with its rear flat face 13 uppermost and flush with the uppersurface 32 of the boss. The diameter of the boss is somewhat less thanthe inside diameter of the clamping rings to permit a certain amount ofradial shifting of the front clamping ring on the base, and the ring ispreliminarily centered by establishing a substantially uniform radialspacing between it and the boss.

With the front clamping ring in place on the fixture, a blade 7 isplaced thereon, with its central portion flatwise overlying the uppersurface 32 of the boss 31 and its peripheral portion overlying theclamping ring. To assist in preliminarily centering the blade, anannular centering guide 35 can be placed over the stud 33 before theblade is set in place. The centering guide has a close sliding fit onthe stud and has an outside diameter slightly smaller than the insidediameter of the blade; hence by inspection the blade can be so placed onthe fixture that there is substantially uniform radial spacing betweenthe blade and the centering guide all around the latter. The centeringguide can then be removed if desired, the stud guiding it in upwardmovement to prevent its engagement with the inner edge of the blade bywhich the blade might be damaged.

At this point the rear clamping ring 14 can be set in place over theperipheral portion of the blade, care being taken to engage the locatingpins 23 in their proper holes so that the clamping rings are lockedthereby in coaxial relationship to one another. Preferably the capscrews 24 are at this time loosely inserted in their holes in theclamping rings. It will be understood that the blade is provided withsomewhat oversize holes through which the locating pins 23 and the capscrews 24 can readily pass.

Next an annular clamping element 36 having a flat bottom surface isplaced over the blade. The clamping element 36 and the boss 31 providethe clamping members by which the blade is confined against edgewisemotion while the clamping rings 13 and 14 are shifted into concentricitywith the blade, according to the method of this invention. The clampingelement 36 has an outside diameter equal to that of the boss 31 and hasan inside diameter somewhat larger than that of the blade so that theinner marginal edge portion of the blade is visible all around the same.To facilitate setting the annular clamping element in place on thefixture and removing it therefrom. it can be provided with a pair oflifting knobs 37 which can comprise thumb screws threaded down into thetop of the clamping element at diametrically opposite locations.

Downward clamping force is applied to the clamping element by means of anut 38 which is threaded onto the upper end ortion of the stud 33 andbears against the hub 39 of a yoke 4-0 having opposite arms extendingradially from the hub to overlie the top of the clamping element. Thestud 33 is closely received in the hub 39 of the yoke.

After the clamping element 3d and yoke 40 are installed on the fixtureand the nut 38 is tightened, the clamping rings can be moved indirections edgewise of the blade, so that they can be brought intoconcentricity to it, while the locating pins 23 hold the clamping ringsin concentric relation to one another.

To facilitate small movements of the clamping rings by which accuratecentering is readily achieved, and to hold them against inadvertentshifting, the fixture is provided with a plurality of circumferentiallyspaced posts 42, in each of which there is threaded a thumb screw 43that extends radially inwardly to have its inner end bear against theouter circumferential surface of the front clamping ring 13. As shown,there are four such thumb screws, located at 90 intervals around thefixture, so that the clamping rings can be slowly moved in any desiredradial direction by turning the appropriate thumbscrew inwardly whilesimultaneously turning outwardly the diametrically opposite thumbscrew.

Although centering of the clamping rings relative to the blade might beaccomplished with the aid of an outside caliper or the like, it ispreferred to use the optical instrumentality illustrated in FIGURES 4, 6and 7, which eliminates the need for physical contact with the inneredge of the blade and which comprises a microscope or magnifying lenssystem 44 and an inverted U-shaped stand 45 upon which the microscope ismounted and which is in turn adapted to rest upon diametrically oppositeportions of the top surface of the rear clamping ring 14. The legs ofthe microscope stand are high enough so that its bight portion clearsthe top of the stud.

At the bottom of one leg of the stand there is a foot 46 (best seen inFIGURES 6 and 7) which extends circumferentially to opposite sides ofsaid leg and carries near each of its ends a roller 47 that is adaptedto ride on the upper face of the rear clamping ring, radially outwardlyof the cap screws 24. The other leg of the stand carries at its bottom asingle roller 48 which likewise rides on the rear clamping ring andcooperates with the rollers 47 to provide a stable and rotatable tripodmounting for the stand. Guide pins 49 project downwardly from the foot46, near the opposite ends thereof and substantially in line with theaxes of the rollers 47, to engage the radially inner surface of the rearclamping ring for concentricity reference. A spring arm 59 (best seen inFIGURE 4) projects downwardly from the foot, circumferentiallyintermediate the guide pins, to engage the outer circumferential surfaceof the rear clamping ring and thus urge the guide pins 49 into firmengagement with its inner edge.

The lens system 44 is provided with a series of parallel calibrationlines 51 (see FIGURE 7) which are adapted to be referenced to the inneredge of the blade, and the microscope is secured to the bight portion ofthe stand 45 by means of an adjustable clamping bracket 52 so that themicroscope can be adjusted along the bight portion to bring itscalibrations into initial register with the inner edge of the blade.Readings are taken with the microscope at locations at which the legs ofthe stand 45 are substantially in line with opposite thumb screws 43, asillustrated in FIGURE 7, and the clamping rings are shifted by means ofsaid thumb screws until they are accurately centered with respect to the:blade, as determined by reference to the microscope calibrations. Notethat the yoke 40 of the clamping element is disposed out of alignmentwith the thumbscrews 43 so that it will not interfere with viewing theinner edge of the blade at the stations which the thumbscrews define.

Since the thumbscrews 4-3 hold the clamping rings against undesiredradial shifting, the microscope stand can be removed from the fixtureafter the clamping rings are centered relative to the blade, tofacilitate tightening of the cap screws 24.

When the cap screws are all tightened, to clampingly secure the bladeagainst displacement relative to the blade holder 12, the nut 38, yokedtl and clamping element 3'5 are removed from the fixture and the bladeholder 12 is turned upside down on the fixture, to dispose the frontclamping ring 13 uppermost, in preparation for use of the fixture toradially tension the blade in accordance with the method of thisinvention.

Referring to FIGURES 3 and 9, it will be noted that the tension ring 17has a generally L-shaped cross-section, with a radially outwardlyprojecting circumferential flange 53 at its front that is adapted tooverlie the fiat front surface of the front clamping ring. The axiallyintermediate portion of the tension ring has an outside diameter such asto provide a close sliding fit in the front clamping ring, and its rearportion is beveled or tapered rearwardly so that at its axially innerend 54 its diameter is substantially smaller than the inside diameter ofthe clamping rings and it is substantially narrow radially.

The function of the tension ring, of course, is to hold the centralportion of the :blade in axially offset relation to its peripheralportion, to thereby maintain circumferential tension in the blade. Hencewhen the tension ring is installed in the blade holder 12 it projectsrearwardly beyond the plane of the axially inner surface 13 of the frontclamping ring, and the distance by which it projects beyond said planedetermines the amount of circumferential tension that it applies to theblade. That distance, in turn, can be controlled by means of shims 55(see FIGURE 3) that are interposed between the front surface of thefront clamping ring 13 and the rear surface of the flange 53 on thetension ring.

In the assembled blade holder the tension ring is re- 7 leasably securedto the front clamping ring by cap screws 56 that extend throughcircumferentially spaced holes in the flange 53 and into coaxialthreaded holes in the front clamping ring, proper alignment of suchholes in the respective rings bring assured by rearwardly projectinglocating pins 57 in said flange that are received in closely fittingholes in the front clamping ring.

If the blade is to be placed under circumferential tension that isuniform all around it, the tension ring must be moved into the frontclamping ring with a purely translatory axial motion. Tightening of thecap screws 56 cannot be relied upon to achieve this. Instead, accord ingto the present invention, the tension ring is loosely assembled into thefront clamping ring and the cap screws 56 are loosely inserted into theholder, and then force is applied coaxially to the tension ring to urgethe same into the front clamping ring until the tension ring reaches aposition at which it effects the desired amount of axial offset of thecentral portion of the blade; and thereafter, while the tension ring ismaintained in that position by the continued application of coaxialforce thereto, the cap screws are tightened to lock the tension ring inthat position.

The apparatus by which such purely translatory axial motion of thetension ring is effected comprises a force applying plate 59 (seeFIGURES 8 and 9) having a central hole in which the stud 33 on thefixture is receivable with a close sliding fit and having a diameter tooverlie the front surface of the tension ring all around the same Whileleaving the cap screws 56 exposed for ready access. The nut 38,cooperates with the plate 59 to apply force to the tension ringuniformly and simultaneously at all points around it. The nut is turneddown on the stud to bear upon the plate 59 and thus drive the tensionring straight down until its flange 53 engages the front face of thefront clamping ring 13 or a shim or shims 55 overlying the same. At thatpoint the tension ring is in the position to cause the desiredtensioning of the blade, and the cap screws 56 are tightened to lock thetension ring in that position. Thereafter the nut 38 can be backed offof the stud and the assembled blade holder can be removed from thefixture for mounting on the chuck.

The reason the blade holder 12 is turned upside down on the fixturebetween the blade centering and blade tensioning steps is to providespacing, during the latter step, between the blade and the flat uppersurface 32 of the central boss 31 on the fixture, so that the centralportion of the blade can be displaced downwardly without interferencefrom the boss. Such spacing of course results from the fact that therear clamping ring has a substantially greater axial thickness than thefront one.

Preferably the blade holder, with the tension ring properly attachedthereto, is assembled to the chuck and accurately balanced before ablade is installed therein and as a final step in manufacture of theapparatus. Provision is made (either by unique locations of the severallocating pins 19, 23 and 57 or by means of marks etched on the severalparts) for assuring that the parts of this balanced assembly will alwaysbe reassembled in the angular relationship to one another that they hadduring the balancing operation. It will be apparent that two 8 balancedblade holder assemblies are desirably provided for a chuck so that ablade can be installed in one holder while the other is in use.

If desired, the base portion of the fixture 28 can be rotatably mountedon a sub-base 60, so as to facilitate the blade centering operation. Thesub-base is preferably provided with a locking screw 61 that isengageable with the base to lock it against rotation relative to the subbase, such locking being desirable when the fixture is in use forinstallation of the tension ring.

From the foregoing description taken together with the accompanyingdrawings it will be apparent that this invention provides a simplemethod and means for accurately centering an annular blade having aninside diameter cutting edge in a holder by which the blade can bemounted on a rotatable chuck, and for circumferentially stressing theblade uniformly all around its inside diameter.

What is claimed as my invention is:

1. The method of installing a thin annular blade having an insidediameter cutting edge in a holder by which the blade can beconcentrically secured to a rotatable chuck, and which holder comprisesa pair of clamping rings having opposable axially inner faces adapted toclanipingly engage the outer marginal edge portion of a blade, saidmethod comprising the steps of:

(A) locking the clamping rings into concentric relation to one anotherwith their said inner faces lightly engaging opposite surfaces of ablade so that the rings are shiftable in unison edgewise relative to theblade;

(B) by clampingly engaging the opposite surfaces of the blade atcircumferentially spaced areas in an annular zone radially intermediatethe inner edge of the blade and the inner circumferences of the clampingrings, confining the blade against edgewise displacement;

(C) while the blade is thus confined, and by reference to the insideedge of the blade and a circumferential surface of one of the clampingrings, shifting the clamping rings edgewise relative to the blade tobring them into a position of concentricity with the blade;

(D) while confining the clamping rings against displacement out of saidposition, drawing them together and locking them in clampingrelationship to the blade; and

(E) releasing the clamping engagement of the blade in said annular zonethereof.

2. The method of claim 1, further characterized by the steps ofcircumferentially tensioning the blade uniformly all around the insidecircumference thereof after the clamping rings are established inclamping relationship to the blade, by the use of a tension ring whichis receivable in one of the clamping rings and which engages a radiallynarrow annular zone of the blade spaced inwardly of the radially innersurfaces of the clamping rings, said steps comprising:

(A) restraining the clamping rings against axial movement;

(B) applying axial force to the tension ring uniformly andsimultaneously at all points around the same to translate the tensionring axially inwardly relative to said one clamping ring until thetension ring reaches a position at which it holds the central portion ofthe blade axially offset from the remainder of the blade by apredetermined distance;

(C) while maintaining axial force on the tension ring to hold it in saidpredetermined position, locking the tension ring to said one clampingring; and

(D) thereafter releasing said axial force on the tension ring, thetension ring retaining its said position by reason of its being lockedto said one clamping ring.

3. The method of establishing a predetermined circumferential tensionall around an annular cutting blade which has an inside diameter cuttingedge and which has its outer marginal edge portion clamped between apair of clamping rings that provide a holder, by the use of a tensionring which is receivable in one of the clamping rings and engages anarrow annular zone of the blade spaced radially inwardly from theradially inner surfaces of the clamping rings, which method comprisesthe steps of:

(A) confining the clamping rings against axial displacement;

(B) applying axial force to an axially outer surface of the tension ringuniformly and simultaneously at all points around the same to move thetension ring into said one clamping ring with a true translatory axialmotion until the tension ring reaches a position at which it holds thecentral portion of the blade axially offset from the remainder of theblade by a predetermined amount; and

(C) while maintaining said axial force at the value to hold the tensionring in said position, locking the tension ring to said one clampingring.

4. The method of installing a thin annular blade having an insidediameter cutting edge in a holder by which the blade can beconcentrically secured to a rotatable chuck and by which the radiallyinner portion of the blade is maintained under circumferential tension,and which holder comprises a pair of clamping rings having opposa-bleflat inner surfaces adapted to clampingly engage opposite faces of theblade at its outer marginal edge portion and a tension ring securable toone of the clamping rings and which has an annular inwardly facingsurface that engages the blade around a radially narrow zone thereof tohold the central portion of the blade axially offset from the outermarginal edge portion thereof and thus maintain the blade undercircumferential ten sion, said method comprising the steps of:

(A) locking the clamping rings in concentric relationship to one anotherand with their said inner faces lightly flatwise engaging oppositesurfaces of a blade around its outer marginal edge portion so that theclamping rings are shiftable in unison relative to the blade indirections edgewise thereof;

(B) clampingly confining the blade against edgewise motion by fiatwiseengaging the opposite faces the-reof in a zone within the embrace of theclamping rings and spaced from the inner marginal edge portion of theblade so that the inner marginal edge portion of the blade is readilyvisible;

(C) by reference to the inner edge of the blade and a circumferentialsurface of one of the clamping rings, and while the blade is clampinglyconfined against edgewise motion, shifting the rings as necessary tobring them into concentricity with the blade;

(D) drawing and holding the clamping rings together in clampingrelationship to the blade to fix them in concentric relationship to it;

(E) confining the clamping rings against axial motion;

(F) inserting the tension ring into one of the clamping rings with anaxial translatory motion by applying axial force uniformly andsimultaneously at all points around the tension ring, until it reaches aposition at which it effects a predetermined axial offset of the centralportion of the blade; and

(G) while maintaining axial force on the tension ring to hold it in saidposition, locking the tension ring to one of the clamping rings.

5. The method of installing a thin annular cutting blade having an inneredge and an outer edge in a holder by which the blade can beconcentrically secured to a rotatable chuck with assurance that theinner edge of the blade which constitutes its cutting edge will beaccurately concentric with the axis of rotation of the chuck, and whichholder comprises a pair of clamping rings having opposable axially inner10 faces adapted to clampingly engage the outer marginal edge portion ofthe blade, said method comprising the steps of:

(A) locking the clamping rings into concentric relation to one anotherwith their said inner faces lightly engaging the opposite sides of theblade, so that relative edgewise shifting can be effected between theblade and the rings;

(B) holding the blade flat by clamping the portion thereof intermediateits inner edge and the inner circumferences of the clamping ringsbetween two fiat rigid surfaces;

(C) while the blade is thus held flat and by reference to the inner edgeof the blade and a circumferential surface of one of the clamping rings,effecting relative edgewise shifting between the blade and the rings asneeded to bring the rings and the inner cutting edge of the blade intoconcentricity;

( 1)) While confining the blade and the clamping rings against relativedisplacement out of concentricity, drawing the clamping rings togetherand locking them in clamping relationship to the blade; and

(E) releasing the blade from the two flat rigid surfaces between whichit was held flat.

6. The method of claim 5, further characterized by the steps ofcircum-ferentially tensioning the blade uniformly all around the insidecircumference thereof after the clamping rings are established inclamping relationship to the blade, by the use of a tens-ion ring whichis receivable in one of the clamping rings and which engages a radiallynarrow annular zone of the blade spaced inwardly of the radially innersurfaces of the clamping rings, said steps comprising:

(A) restraining the clamping rings against axial movement:

(B) applying axial force to the tension rin-g uniformly andsimultaneously at all points around the same to translate the tensionring axially inwardly relative to said one clamping ring until thetension ring reaches a position at which it holds the central portion ofthe blade axially ofiset from the remainder of the blade by apredetermined distance;

(C) while maintaining axial force on the tension ring to hold it in saidpredetermined position, locking the tension ring to said one clampingring; and

(D) thereafter releasing said axial force on the tension ring, thetension ring retaining its said position by reason of its being lockedto said one clamping ring.

7. Apparatus for installing a thin annular cutting blade having an innercutting edge and an outer edge, in a holder by which the blade can beconcentrically secured to a rotatable chuck, with assurance that theinner cutting edge of the blade will be accurately concentric with theaxis of rotation of the chuck, and which holder comprises a pair ofclamping rings having opposable axially inner that faces adapted toclampingly engage the outer marginal edge portion of the blade,cooperating locating means on the clamping rings for non-clampinglylocking them in concentric relation to one another so that they may beshifted in unison edgewise relative to a blade loosely received betweentheir inner faces, and cooperating force applying means on the clampingrings for establishing them in clamping relationship to a bladetherebetween,

said apparatus comprising:

(A) a base having (1) an annular upwardly facing surface on which one ofthe clamping rings may be set with its flat inner face uppermost, and

(2) a central boss, the top of which provides an elevated planar surfacewhich is uniformly spaced above said annular surface by a distance equalto the thickness of said one ring,

1 1 so that when said one ring is set on said annular surface with itssaid flat inner face uppermost, that face lies in the plane of saidplanar top surface of the boss;

(B) an upright stud on the base coaxial with the central boss andprojecting upwardly from the top of the boss;

(C) an annular clamping member encircling the stud and cooperable withsaid elevated planar top surface of the boss to clampingly con-fine ablade placed on the boss against edgewise displacement,

said clamping member being of a size to engage the blade at an areathereof that is radially spaced from its inner and outer edges,

so that the clamping member does not interfere with placement of theother clamping ring on the outer marginal edge portion of the blade andso that the clamping member leaves visible substantially all the innermarginal edge portion of the blade;

(D) means cooperable with the clamping member and the stud for applyingdownward clamping force to the clamping member to thereby securely clampthe blade to the base; and

(E) circu-mferentially spaced means fixed with respect to the base andengageable with one of the clamping rings for adjustably shifting theclamping rings in unison and edgeWise of the blade in directions radialto the blade as needed to bring the rings into concentricity with theblade as determined by the spacial relationship between the inner edgeof the base and a circumferential surface on one of the clamping rings.

8. The apparatus of claim 7, further characterized by means tofacilitate ascertaining the spacial relationship between the innercutting edge of the blade and said circumferential surface on one of theclamping rings, comprising a frame member having spaced legs adapted toset on the upper surface of the uppermost clamping ring and therebysupport the frame for stable rotation about the common axis of theconnected clamping rings,

means on the frame guidingly engageable with a circumferential surfaceportion of one of the connected clamping rings to constrain the frame torotation about the common axis of the clamping rings, and

optical means on the frame through which the inner edge of the blade canbe observed, and having calibrations referable to the inner edge of theblade to facilitate observation of departures of the blade fromconcentricity with said circumferential surface on said one of theconnected clamping rings as the frame is rotated.

References Cited UNITED STATES PATENTS OTHER REFERENCES InstructionManual Model l/D Micro-Slicer, December 1964, Doall Co., Des Plaines,111.

JOHN F. CAMPBELL, Primary Examiner.

5 THOMAS H. EAGER, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,324,539 Dated June 1967 Inventor-(S) C-E. Cleland It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 11, line 31 (Claim 7, element E, line 7 thereof): "base" shouldread blade SIGNED AND SEALED MM. Flmher, 1'. WILLIAM I- I Oomissioner ofmm Atteslmg Oificer FORM 30.1050 (o-s9) USCOMM-DC 6OS76-P09 Q {LiGOVIINMINY FHINYING OFFICE illl O'-l-$,l

1. THE METHOD OF INSTALLING A THIN ANNULAR BLADE HAVING AN INSIDEDIAMETER CUTTING EDGE IN A HOLDER BY WHICH THE BLADE CAN BECONCENTRICALLY SECURED TO A ROTATABLE CHUCK, AND WHICH HOLDER COMPRISESA PAIR OF CLAMPING RINGS HAVING OPPOSABLE AXIALLY INNER FACES ADAPTED TOCLAMPINGLY ENGAGE THE OUTER MARGINAL EDGE PORTION OF A BLADE, SAIDMETHOD COMPRISING THE STEPS OF: (A) LOCKING THE CLAMPING RINGS INTOCONCENTRIC RELATION TO ONE ANOTHER WITH THEIR SAID INNER FACES LIGHTLYENGAGING OPPOSITE SURFACES OF A BLADE SO THAT THE RINGS ARE SHIFTABLE INUNISON EDGEWISE RELATIVE TO THE BLADE; (B) BY CLAMPINGLY ENGAGING THEOPPOSITE SURFACES OF THE BLADE AT CIRCUMFERENTIALLY SPACED AREAS IN ANANNULAR ZONE RADIALLY INTERMEDIATE THE INNER EDGE OF THE BLADE AND THEINNER CIRCUMFERENCES OF THE CLAMPING RINGS, CONFINING THE BLADE AAGAINST EDGEWISE DISPLACEMENT; (C) WHILE THE BLADE IS THUS CONFINED, ANDBY REFERENCE TO THE INSIDE EDGE OF THE BLADE AND CIRCUMFERENTIAL SURFACEOF ONE OF THE CLAPMPING RINGS, SHIFTING THE CLAMPING RINGS EDGEWISERELATIVE TO THE BLADE TO BRING THEM INTO A POSITION OF CONCENTRICITYWITH THE BLADE; (D) WHILE CONFINING THE CLAMPING RINGS AGAINSTDISPLACEMENT OUT OF SAID POSITION, DRAWING THEM TOGETHER AND LOCKINGTHEM IN CLAMPING RELATIONSHIP TO THE BLADE; AND (E) RELEASING THECLAMPING ENGAGEMENT OF THE BLADE IN SAID ANNULAR ZONE THEREOF.